Getting the best from beet

It became clear that, as a sector, we needed a better understanding of FB’s benefits and risks, and how to manage it for optimal outcomes. And so, DairyNZ and collaborators, with funding from DairyNZ, MPI and PGGW Seeds, have been researching these areas and developing management guidelines for use in NZ systems. 

Initial research (2009-2012) focused on the nutritional aspects of FB feeding, while more recent research (2018-2022) has investigated the plant’s environmental opportunities. Currently, we’re identifying sustainable feeding regimes for optimal production and environmental outcomes. 

This article summarises what we know so far, with particular emphasis on FB’s environmental opportunities and our recommendations for feeding to minimise nutritional risk.

Environmental opportunities

Until recently, the environmental priority for dairy farmers has been to reduce nitrogen (N) leaching. However, new greenhouse gas reduction targets (Zero Carbon Act) mean farmers are now also looking for ways to reduce methane and nitrous oxide (N₂O) emissions. Our research shows FB could be one tool in the kit.

Nitrate leaching

Fodder beet has low crude protein (CP; less than 12 %) but high soluble sugar content (more than 50%). This means it can reduce cows’ urinary nitrogen excretion1 and subsequent N leaching. Research results also suggest urine from cows grazing FB may contain a biological nitrification inhibitor, which offers potential to further reduce N leaching and N₂O emissions².

N leaching from winter-grazed FB (82kg N/ha) at the Southern Dairy Hub was 50% lower than for winter-grazed kale (176kg N/ha)³. After accounting for differences in crop yield, daily feed allocation and the area required for each crop, wintering on FB reduced N leaching by up to 60% compared with kale (Table 1).

Nitrous oxide

Nitrous oxide emissions from urine patches of cows grazing FB in Canterbury were 39% lower than from cows grazing kale, despite both having the same rate of nitrogen deposition (300kg N/ha; Figure 1)⁴. In addition to the proposed presence of biological nitrification inhibitors in urine, researchers have proposed the existence of inhibitors in the soil of FB paddocks, which could reduce N₂O emissions⁵.

Methane 

While dry matter intake is the key driver of methane output, recent research suggests feed type also contributes. Dry cows grazing FB with pasture silage in Canterbury produced 18% less methane (g/day) and had 28% lower methane yield (g/kg dry matter; DM intake) than cows grazing kale with barley straw6. Similarly, lactating cows grazing pasture and FB (3kg DM/cow/day) produced 18% less methane and had 16% lower methane intensity (g/kg milk production) than cows fed pasture only, while milk production and methane yield were similar⁶. 

Minimising nutritional risks 

To capitalise on FB’s potential environmental benefits, feeding regimes need to minimise the known nutritional risks. This starts with knowing what you’re feeding and carefully transitioning animals onto the crop. 

Before feeding FB, we recommend you measure crop yield, and feed-test the leaf and bulb separately (from all paddocks) and the supplements you’ll offer, to determine the diet nutritional content. With this information, you can determine the most appropriate management to minimise acidosis risk and maximise the likelihood of meeting animal nutrient requirements.

Acidosis 

Research shows that feeding lactating dairy cows a diet containing 60% FB with pasture, or dry cows a diet containing 85% FB with barley straw, provides inadequate nutrition. Half of the cows on these diets developed clinical rumen acidosis^7,8. At the Southern Dairy Hub (SDH) in winter 2022, four out of 180 cows developed clinical acidosis during transitioning onto FB. Collar data identified another 26 animals with significantly decreased rumination activity, indicating sub-clinical acidosis. This event highlighted the value of cow wearable technologies (collars, tags, boli) in early detection and management of animal health issues. Sub-clinical acidosis may explain a reduction in milk production when FB was offered as 40% of the diet in late lactation⁹. 

Meeting protein and mineral requirements 

The nutrient imbalances of FB diets can result in cows having lower blood phosphorus (P), total protein and urea levels than when they’re grazing kale¹⁰. This reflects deficiencies in P, protein and fibre. While blood P doesn’t reflect the full P status of cows, researchers have observed declining concentrations with time on crop, indicating cows weren’t able to maintain blood P levels through metabolism of bone reserves. So, to reduce the risk of P deficiency at calving, and to ensure bone mineral levels aren’t depleted, P supplementation for cows is recommended while they’re consuming FB¹⁰. 

Pre-calving management 

As cows approach calving, they need more protein to support increased foetal growth and to develop mammary tissue. For cows on FB, this often coincides with a fall in protein intake, as FB has a higher proportion (up to 90%) of low-proteincontaining bulbs.

It’s important to ensure you’re offering sufficient protein in late pregnancy. Either transition cows off FB four weeks pre-calving or offer a higher-protein supplement or pasture alongside the FB. 

In-calf dairy cows on low-protein FB crops often ‘bag up’ closer to calving than those on grass or kale, increasing the risk of calving on crop. Here are some simple ways to reduce this risk:

• Early pregnancy scan to accurately date pregnancies.
• Understand the implications of bull gestation length on expected calving date. 
• Don’t rely solely on visual appearance of the udder for springer drafting.

Milk production 

Currently, there’s not enough research to conclude how wintering on FB or supplementing pasture with FB affects milk production and milk composition. Researchers have seen improved milksolids yield among cows wintered on FB, compared with those wintered on kale¹¹. Another study showed no difference in milk production for first-lactation heifers wintered on either FB or kale (Woods, R., submitted). 

Recent farm systems research has observed lower peak and whole lactation milksolids production from herds wintered on FB and supplemented with FB in early and late lactation compared with cows wintered on kale and offered 50:50 barley:PKE as their lactation supplement. Varying results relating to FB and milk production may reflect the variation of animal physiological state or nutritional composition of the diet¹². 

Fodder beet research continuing 

Four years of data coming out of farm systems research at SDH (milk, repro, financial etc.) is currently being analysed to update our knowledge on FB feeding at a systems level. Fodder beet will continue to be included in two of the proposed farm systems starting at SDH in June 2023.

Get more helpful information on fodder beet, including podcasts and our FeedChecker calculator.

Key points 

Fodder beet has potential environmental benefits, with research showing reductions in nitrogen leaching, nitrous oxide emissions and methane production in NZ, but it requires careful management. 

To minimise the nutritional risks from feeding fodder beet: 

• Test crops and supplements for nutritional value, so you know what you’re feeding 
• Ensure nutrient requirements are being met for all stock, especially in the four weeks prior to calving and for youngstock. 

Successful feeding requires attention to detail throughout the planning and feeding process. Farmers feeding fodder beet successfully use the following guiding principles: 

• Plan – paddock selection and setup, feed budgeting, strategies for meeting nutrient requirements and minimising environmental risks.
• Measure – crop yield, feed quality, body condition score, animal mineral levels.
• Observe – animal health especially during transitioning, growth rates of youngstock.

References

1. Dalley, D. E., B. J. Malcolm, E. Chakwizira, and J. M. de Ruiter. 2017. Range of quality characteristics of New Zealand forages and implications for reducing the nitrogen leaching risk from grazing dairy cows. New Zealand Journal of Agricultural Research 60: 319-332. 

2. Talbot, W. D., B. J. Malcolm, K. C. Cameron, H. J. Di, and D. Whitehead. 2020. Cattle diet and winter plant growth effects on nitrogen losses from cattle urine patches. Nutrient Cycling in Agroecosystems 116: 365-379.

3. Smith, C. and R. Monaghan. 2020. Nitrogen leaching losses from fodder beet and kale crops grazed by dairy cows in southern Southland. Journal of New Zealand Grasslands 82: 61-71. 

4. Di, H. J., K. C. Cameron, A. Podolyan, G. R. Edwards, C. A. M. de Klein, R. Dynes, and R. Woods. 2016. The potential of using alternative pastures, forage crops and gibberellic acid to mitigate nitrous oxide emissions. Journal of Soils and Sediments 16: 2252- 2262. 

5. Yao, B., H. J. Di, K. C. Cameron, A. Podolyan, J. Shen, and J. He. 2018. Understanding the mechanisms for the lower nitrous oxide emissions from fodder beet urine compared with kale urine from dairy cows. Journal of Soils and Sediments 18: 85-93. 

6. Jonker, A., D. Scobie, R. Dynes, G. Edwards, C. de Klein, H. Hague, R. McAuliffe, A. Taylor, T. Knight, and G. Waghorn. 2017. Feeding diets with fodder beet decreased methane emissions from dry and lactating dairy cows in grazing systems. Animal Production Science 57: 1445-1450.

7. Waghorn, G., N. Law, M. Bryant, D. Pacheco, and D. Dalley. 2019. Digestion and nitrogen excretion by Holstein-Friesian cows in late lactation offered ryegrass-based pasture supplemented with fodder beet. Animal Production Science 59: 1261-1270. 

8. Waghorn, G., K. Collier, M. Bryant, and D. Dalley. 2018. Feeding fodder beet (Beta vulgaris L.) with either barley straw or pasture silage to non-lactating dairy cows. New Zealand Veterinary Journal 66: 178-185. 

9. Dalley, D., D. Waugh, A. Griffin, C. Higham, J. de Ruiter, and B. Malcolm. 2020. Productivity and environmental implications of fodder beet and maize silage as supplements to pasture for late lactation dairy cows. New Zealand Journal of Agricultural Research 63: 145-164.

10. Dalley, D. E., J. P. Edwards, E. Masterson, and R. R. Woods. 2021. The effect of winter fodder beet or kale allocation on behaviour and blood metabolite status of non-lactating dairy cows. Journal of New Zealand Grasslands 83: 153-162. 11. Dalley, D. E., J. P. Edwards, and R. R. Woods. 2020. Impact of winter fodder beet or kale allocation on body condition score gain and early lactation performance of dairy cows. Journal of New Zealand Grasslands 82: 73-81. 

12. Fleming, A. E. 2020. A rumen, animal and farm systems evaluation of fodder beet when used to supplement ryegrass during lactation. Department of Agricultural Sciences, Lincoln University: C